System for aiding the preparation of operation and maintenance plans for a power generation installation

ABSTRACT

In order to provide an operation and maintenance planning aiding system for a power generation installation which prepares an operation plan for a plurality of power generation units by making use of actual plant data and based on a total judgement including a variety of circumstances of the machine and apparatus or the parts thereof in the power generation units, in the system the plurality of power generation units  41, 42, 51  and  52 , a power supply command center  3  and a service center  1  are arranged and connected via a communication network  6 , the service center  1  obtains the plant data via the communication network  6  from the plurality of power generation units  41, 42, 51  and  52 , calculates in real time a power generation efficiency of a concerned power generation unit for every plurality of power generation units  41, 42 51  and  52  by making use of the obtained plant data and design data of the concerned power generation unit and prepares an operation and maintenance plan for each of the power generation units based on the calculated power generation efficiency.

This application is a continuation of application Ser. No. 10/218,488,filed Aug. 15, 2002, now U.S. Pat. No. 6,691,065 which is a continuationof application Ser. No. 09/952,024, filed Sep. 14, 2001 now U.S. Pat.No. 6,853,930.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system for aiding the preparation ofan operation and maintenance plan for a power generation installation,and, in particular, relates to an operation and maintenance planpreparation aiding system for a power generation installation, in whicha service center is provided. The service center manages operation andmaintenance of a plurality of power generation units and prepares anoperation and maintenance plan for respective power generation units bymaking use of plant data obtained from the respective power generationunits through a communication network.

2. Conventional Art

Generally, many electric power generation companies, which operate anelectric power generation business, own a plurality of power generationunits. In order to manage the amount of power generated by these powergeneration units as a whole, comprise respective power generationsystems are provided with a power supply command center (central supply)for every electric power generation company. In such power generationsystems, the power supply command center assigns and adjusts the powergeneration amount for every power generation unit in response to powerdemand from consumers and each of the power generation units performs anoperation while maintaining and adjusting the power generation amountassigned by the power supply command center. In such instances, thepower supply command center prepares, in view of enhancing economy, anoperation plan for the concerned power generation system so as tominimize fuel cost used in the power generation units, and to maximizepower generation efficiency. As well, the command center prepares aplan, in view of placing priority on environmental protection, to keepthe exhaust gas amount, such as nitrogen oxides and carbon dioxidesexhausted from the power generation units, within an allowable range.

Now, the characteristics with regard to power efficiency and the exhaustgas amount which are used as references for the operation planning varygreatly depending on the kinds of fuel used and the power generationmethods. With regard to fuels, in case of a thermal power generation,many kinds of fuels such as coal, petroleum and natural gas can be used,therefore, depending on the kind of fuels used, not only the powergeneration amount per unit fuel cost but also the amount and contents ofthe exhaust gas vary greatly. Further, with regard to power generationmethods, the constitutions of machines and apparatuses of themselvessuch as power generation by a steam turbine, power generation by a gasturbine and a combined power generation combining thereof affect greatlytheir power generation efficiency. The power supply command centerstores and preserves plant data (data representing the plantcharacteristics) obtained from these power generation units for everypower generation unit, and uses the plant data when preparing operationplans for respective power generation units.

In the above referred to conventional power generation system, althoughthe power supply command center stores and preserves the plant data forevery power generation unit, these plant data were limited to the plantdata at comparatively early stage of the respective power generationunits, such as design values and those at the operation starting periodof the power generation plants, however, the plant data varies graduallydepending on passage of time as well as the contents of fuel being used,which also varies, therefore, it is difficult to prepare operation plansbased on the current plant characteristics of the respective powergeneration units by making use only of the plant data.

Further, the above referred to conventional power generation system,since the machines and apparatuses such as a gas turbine constitutingthe power generating unit are always exposed to a high temperature, ifload variation to the machines and apparatuses is frequently andrepeatedly caused, deterioration of the machines and apparatuses due tothermal fatigue rapidly advances. For this reason, even if a fullyeconomic operation which simply minimizes fuel cost for respective powergeneration units is employed, when the load variation to the machinesand apparatuses is repeated, the lifetime of the machines andapparatuses is shortened, thus quickening the exchange time thereof, andtherefore the total cost for the respective power generation unitsnecessary for the plant operation, including the maintenance cost, isnot necessarily minimized. Further, in the above referred toconventional power generation system, even if a plurality of powergeneration units having a high power generation efficiency arepositively selected for the operation, when a provability of failure ofthe machines and apparatuses and the parts thereof constituting thepower generation unit concerned is high, an unplanned outage is causedby a failure occurrence in the machines and apparatuses and the partsthereof which possibly causes an economic loss, therefore, even when anoperation plan for a plurality of power generation units is preparedonly based on fuel cost, the resultant cost was not necessarilyminimized.

SUMMARY OF THE INVENTION

The present invention has been achieved in view of the above technicalbackground, and an object of the present invention is to provide asystem for aiding in the preparation of an operation and maintenanceplan for a power generation installation in which an operation plan fora plurality of power generation units is prepared by making use ofactual plant data, and being based on a total judgement, including avariety of circumstances of the machines and apparatuses and the partsthereof in the power generation units.

A first aspect of the present invention is to provide a system foraiding in the preparation of an operation and maintenance plan for apower generation installation in which a plurality of power generationunits, a power supply command center and a service center are arrangedand connected via communication networks, the service center obtainingplant data from the plurality of power generation units via therespective communication networks. For every power generation unit, theservice center calculates power generation efficiency for the concernedpower generation units in real time by making use of the obtained plantdata and design data of the concerned power generation units andprepares operation and maintenance plans for the respective powergeneration units based on the calculated power generation efficiency.

According to the first aspect of the present invention, since theoperation and maintenance plans for the respective power generationunits are prepared in the service center based on the power generationefficiency evaluated and calculated in real time, a secular change and aperformance degradation due to failure occurrence for the respectivepower generation units can be taken into account, thereby, the operationcost thereof can be reduced in comparison with the conventional powergeneration system in which the operation and maintenance plans for therespective power generation units are prepared by making use of theplant data.

A second aspect of the present invention is to provide a system foraiding in the preparation of an operation and maintenance plan for apower generation installation in which a plurality of power generationunits, a power supply command center and a service center are arrangedand connected via communication networks, the service center obtainsplant data from the plurality of power generation units via therespective communication networks, and for every power generation unit,estimates process values in a machine and apparatus model by making useof the obtained plant data, determines deviation values between theestimated values and measured values, calculates from the determineddeviation value a cost of economical loss caused by a power generationefficiency reduction of the concerned power generation unit, andprepares operation and maintenance plans for the respective powergeneration units through comparison between the calculated cost ofeconomical loss and a cost relating to exchange of the machine andapparatus and the parts thereof in the concerned power generation unit.

According to the second aspect of the present invention, when preparingthe operation and maintenance plans for the respective power generationunits in the service center based on the power generation efficiencyevaluated and calculated in real time, since the cost of economical lossdue to the performance degradation is calculated from the deviationvalue between the process value estimated with the machine and apparatusmodel and the measured value, the cost of economical loss is comparedwith the cost relating to the exchange of the machine and apparatus andthe parts thereof and the operation and maintenance plan of therespective power generation units are prepared by making use of thecomparison result, the total cost for the operation and maintenance canbe reduced.

A third aspect of the present invention is to provide a system foraiding in the preparation of an operation and maintenance plan for apower generation installation in which a plurality of power generationunits, a power supply command center and a service center are arrangedand connected via communication networks. The service center obtainsplant data from the plurality of power generation units via therespective communication networks. For every power generation unit, theservice center calculates remaining lifetime of the machine andapparatus and the parts thereof in the concerned power generation unitby making use of the obtained plant data and prepares operation andmaintenance plans for the respective power generation units bydetermining exchange time of the machine and apparatus and the partsthereof in the concerned power generation unit based on the calculatedremaining lifetime thereof.

According to the third aspect of the present invention, when preparingthe operation and maintenance plans for the respective power generationunits in the service center based on the power generation efficiencyevaluated and calculated in real time, since the operation andmaintenance planes are prepared based on the calculated remaininglifetime, an exchange timing of the machine and apparatus and the partsthereof can be determined with high accuracy in comparison with theconventional power generation system in which exchange of the machineand apparatus and the parts thereof is performed with reference to anaccumulated operation time thereof, as a result, an abnormalityoccurrence due to use of the machine and apparatus and the parts thereofexceeding their lifetime and generation of economical loss due tounplanned outages caused by an abnormality of the machine and apparatusand the parts thereof can be prevented, moreover, an exchange at everypredetermined period of the machine and apparatus even if there is aremaining lifetime is unnecessitated, thereby, the maintenance cost canbe reduced.

A fourth aspect of the present invention is to provide a system foraiding in the preparation of an operation and maintenance plan for apower generation installation in which a plurality of power generationunits, a power supply command center and a service center are arrangedand connected via communication networks, the service center obtainingplant data from the plurality of power generation units via therespective communication networks and, for every power generation unit,calculating remaining lifetime of the machine and apparatus and theparts thereof in the concerned power generation unit by making use ofthe obtained plant data, comparing the calculated remaining lifetimewith remaining lifetime of the machine and apparatus in the powergeneration unit determined in the other power generation unit, modifyingthe operation condition for the machine and apparatus and the partsthereof so as to enhance economy and prolong or shorten the remaininglifetime of the machine and apparatus and the parts thereof in theconcerned power generation unit, thereby, preparing the operation andmaintenance plans for the respective power generation units.

According to the fourth aspect of the present invention, when preparingthe operation and maintenance plans for the respective power generationunits in the service center based on the power generation efficiencyevaluated and calculated in real time, since the operation condition forthe machine and apparatus in its own power generation unit is modifiedbased on the remaining lifetime of the machine and apparatus and theparts thereof not only in its own power generation unit but also inanother power generation unit, the operation and maintenance plans canbe prepared so that the total cost necessary for the operation andmaintenance for the respective power generation units is minimized, thecost merit obtained by the electric power generation by the electricpower generation company can be increased in comparison with theconventional power generation system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a first embodiment of thepresent invention;

FIG. 2 is a block diagram of an exemplary constitution of a powergeneration unit as shown in FIG. 1;

FIG. 3 is a block diagram of an exemplary constitution of a servicecenter as shown in FIG. 1;

FIG. 4 is a view for explaining storage contents of a process valuedatabase as shown in FIG. 3 and shows a structure of the process data;

FIG. 5 is a view for explaining storage contents of a design informationdatabase as shown in FIG. 3 and shows a structure of the designinformation data;

FIG. 6 is a view for explaining storage contents of a machine andapparatus model database and shows a structure of the machine andapparatus model data;

FIG. 7 is a view for explaining a schematic constitution of a gasturbine;

FIG. 8 is a characteristic diagram showing a secular change of anelectric power output between an estimated value using a machine andapparatus model and an actually measured value obtained from a powergeneration unit;

FIG. 9 is a characteristic diagram showing an analysis example of anefficiency diagnosis performed in an efficiency diagnosis unit;

FIG. 10 is a view for explaining storage contents of a periodicinspection database, and shows a structure of the periodic inspectioninformation data;

FIG. 11 is a view for explaining storage contents of a machine and aapparatus database, and shows a structure of the machine and apparatusinformation data;

FIG. 12 is a view for explaining storage contents of a materialinformation database;

FIG. 13 is a graph obtained by plotting a variation condition of alifetime consumption value with respect to time;

FIG. 14 is a flow chart showing a processing flow when an operation planevaluation unit prepares an operation plan by making use of remaininglifetime data;

FIG. 15 is a view for explaining storage contents of a failureinformation database, and shows a structure of the failure informationdata;

FIG. 16 is a view for explaining storage contents of a manufacturerinformation database, and shows a structure of the manufacturerinformation data;

FIG. 17 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a second embodiment of thepresent invention;

FIG. 18 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a third embodiment of thepresent invention;

FIG. 19 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a fourth embodiment of thepresent invention;

FIG. 20 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a fifth embodiment of thepresent invention;

FIG. 21 is a view for explaining storage contents of another processvalue database as shown in FIG. 3 and shows a structure of the processdata;

FIG. 22 is a view for explaining storage contents of another designinformation database as shown in FIG. 3 and shows a structure of thedesign information data;

FIG. 23 is a view for explaining storage contents of another periodicinspection database, and shows a structure of the periodic inspectioninformation data;

FIG. 24 is a view for explaining storage contents of another failureinformation database, and shows a structure of the failure informationdata;

FIG. 25 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a sixth embodiment of thepresent invention;

FIG. 26 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a seventh embodiment of thepresent invention; and

FIG. 27 is a characteristic diagram showing selection principle of powergeneration units.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, embodiments of the present invention will be explained withreference to the drawings.

FIG. 1 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a first embodiment of thepresent invention.

As shown in FIG. 1, the operation and maintenance plan preparationaiding system for a power generation installation is constituted by aservice center 1, which performs the business of preparing an operationand maintenance plan, an electric power generation company 2, which ownstwo power generation plants 4 and 5, a power supply command center(central supply) 3, which commands power generation output amounts tothe two power generation plants 4 and 5 in response to power demandamount, A power generation plant 4 including two power generation units41 and 42, B power generation plant 5 including two power generationunits 51 and 52 and a communication network 6 such as the internet. Inthe present embodiment, the service center 1, the power supply commandcenter 3, the power generation units 41 and 42, the power generationunit 51 and 52 are selectively connected via the communication network6.

The electric power generation company 2 requests the service center 1 toprepare an operation and maintenance plan for the power generation units41 and 42 owned by the A power generation plant 4 and the powergeneration units 51 and 52 owned by the B power generation plant 5.

Now, FIG. 2 is a block diagram of an exemplary constitution of the powergeneration unit 41 as shown in FIG. 1, and FIG. 3 is a block diagram ofan exemplary constitution of the service center 1 as shown in FIG. 1.

As shown in FIG. 2, the power generation unit 41 includes, at the sideof a main body 411 of the power generation unit 41, a first sensor 412for detecting a first process value, a second sensor 413 for detecting asecond process value, a first control unit 414 for controlling a firstportion in the main body 411, a second control unit 415 for controllinga second portion in the main body 411 and a process computer 416 forconverting the first and second process values into transmissionsignals, and other than the above is provided with a process valuetransmission unit 417 and a fire wall 418 for performing communication.In a conventional power generation unit, a process computer has thefunction of computing processing values detected by the first and secondsensors and all of the process values necessary for operating the powergeneration unit are stored in the database. The process valuetransmission unit 417 obtains process values from the database in theprocess computer 416, and transmits the same to the communicationnetwork 6 via the fire wall 418. At the moment of transmitting theprocess values, transmission time information and an ID for specifyingthe power generation unit are transmitted altogether. Further, in thepresent embodiment, since the internet is used as the communicationnetwork 6, a fire wall 418 is provided in order to prevent unauthorizedaccess to the power generation unit 41 from outside, however, if anexclusive line is used in the communication network 6, the fire wall 418can be omitted.

Further, as shown in FIG. 3, the service center 1 is constituted by afire wall 11, a process value receiving unit 12, a process valuedatabase 13, a machine and apparatus model database 14, a materialinformation database 15, a failure information database 16, amanufacturer information database 17, a design information database 18,an efficiency diagnosis unit 19, a remaining lifetime diagnosis unit 20,a failure frequency evaluation unit 21, a manufacturer priorityevaluation unit 22, an electric power demand amount receiving unit 23,an operation plan information transmission unit 24, an operation planevaluation unit 25, a periodic inspection information database 26 and amachine and apparatus information database 27, and these elements 11through 27 are mutually connected as shown in FIG. 3.

In the power generation unit 41, when the process value transmissionunit 417 transmits process data, which is transferred via thecommunication network 6 to the side of the service center 1, the servicecenter 1 obtains via the fire wall 11 the process data, transfers theobtained process data from the process value receiving unit 12 to theprocess value database 13 and stores the same therein. Further, otherprocess data transferred from other power generation units 42, 51 and 52are likely stored in the process value database 13.

Herein, FIG. 4 is a view for explaining the storage contents in theprocess value database as shown in FIG. 3 and shows a structure of theprocess data.

As shown in FIG. 4, each of the process data is assigned a processnumber representing ID for discriminating process values for every powergeneration unit and is managed according to the process number. In thepresent embodiment, the service center 1 obtains process data in apredetermined cycle from the respective power generation units 41, 42,51 and 52 and, in the present first embodiment as will be seen from thecontents with regard to the time the process data is stored in theprocess value database 13, the service center 1 obtains the process datain a cycle of 1 sec.

The power supply command center 3 transmits a power demand amountrequired to be supplied by the electric power generation company 2 aspower demand information to the service center 1 via the communicationnetwork 6. Since the power demand information varies from time to timedepending on power demand, the information is transmitted in apredetermined cycle, for example, every 1 sec. to the service center 1.The service center 1 receives the power demand information via the firewall 11 at the power demand amount receiving unit 23, and supplies thereceived power demand information to the operation plan evaluation unit25. In this instance, the operation plan evaluation unit 25 distributespower generation amounts for the respective power generation units 41,42, 51 and 52 so that the summed value of the power generation amountsof the respective power generation unit 41, 42, 51 and 52 coincides withthe required value, and supplies the distribution result to theoperation plan information transmitting unit 24. The operation planinformation transmitting unit 24 transmits the operation planinformation, namely the power generation amount information distributedto the respective power generation units 41, 42, 51 and 52 to the powersupply command center 3 via the communication network 6. The powersupply command center 3 confirms the contents of the operation planinformation sent from the service center 1 and outputs the commandvalues of the power generation amount for the respective powergeneration units 41, 42, 51 and 52 according to the operation planinformation.

The explanation until now relates to operation planning in response topower demand which varies from time to time in the operation andmaintenance plan preparation aiding system for a power generationinstallation, however, other than the above, the present operation andmaintenance plan preparation aiding system for a power generationinstallation also prepares a long term operational plan. For example,the system prepares such maintenance plans in which, based on the plantdata obtained on-line, conditions of the machine and apparatus and theparts thereof in the power generation units are judged, such thatdisassembling and inspection of the power generation units andexchanging of the parts thereof are performed according to the judgementresult, and the timing of the periodic inspection of the powergeneration units is adjusted.

The above is an outline of the service which the service center 1provides to the electric power generation company 2.

Hereinbelow, details of processing steps performed by the service center1 for preparing the operation and maintenance plan will be explained.

The service center 1 uses power generation efficiency in the respectivepower generation units as one of the parameters for preparing theoperation plan. Hereinbelow, the processing for calculating the powergeneration efficiency will be explained.

In the service center 1 as shown in FIG. 3, the evaluation of the powergeneration efficiency is performed at the efficiency diagnosis unit 19,which investigates models of the machine and apparatus constituting thepower generation unit with reference to the design information database18.

FIG. 5 is a view for explaining the storage contents of the designinformation database 18 as shown in FIG. 3, and shows the structure ofthe design information database.

As shown in FIG. 5, the design information data are constituted bymachines and apparatus and parts thereof constituting the respectivepower generation units and their supplying manufacturers and types forevery machine, apparatus and part. For example, in the case of a firstpower generation unit (power generation unit 1) in power plant A, aproduct of A company of type GT001 is employed as a gas turbine, and asparts constituting the gas turbine, a combustor of B company of typeCB003, a turbine of A company of type TB001 and a compressor of Acompany of type CP001 are employed.

Further, the efficiency diagnosis unit 19 refers to a machine andapparatus model in the machine and apparatus model database 14 in orderto calculate the power generation efficiency.

FIG. 6 is a view for explaining the storage contents in the machine andapparatus model database 14 and shows the structure of the machine andapparatus data.

As shown in FIG. 6, the machine and apparatus model data are constitutedby parts or types and machine and apparatus model for every part andtype, and the substance of the machine and apparatus model is a programoperable on a computer. Further, each of the machine and apparatus modeldata is provided with a process number for the process value serving asan input and output of the program for every machine and apparatusmodel.

The efficiency diagnosis unit 19 causes the program to operate accordingto the input and output specifications stored in the machine andapparatus model database 14.

Now, processing steps which perform the efficiency diagnosis by makinguse of the machine and apparatus model will be explained.

FIG. 7 is a view for explaining an outline constitution of a gasturbine. As shown in FIG. 7, a gas turbine is constituted by acompressor, a combustor and a turbine. Between these elements air,combustion gas or fuel flows. For example, when the machine andapparatus model as shown in FIG. 7 is constituted by a combination ofmachine and apparatus models of the compressor, combustor and turbinestored in the machine and apparatus model database 14, a performance ofthe gas turbine as a whole can be calculated by calculating theperformances of the respective machine and apparatus models. Namely, asshown in FIG. 7, when measured values such as fuel, shaft rpm, flow rateof intake air and temperature are set at the inputs of the machine andapparatus model, then values such as electrical power output and exhaustgas temperature to be output under the set conditions can be estimated.The calculation is performed under the precondition that the respectivemachine and apparatus models are operated normally. Therefore, when adeviation is caused between the estimated value determined by making useof machine and apparatus models and the actually measured value obtainedfrom the plant data, it can be judged that the power generation unitgenerating such plant data is deviating from a normal condition.

FIG. 8 is a characteristic diagram showing a secular change of anelectric power output between the estimated value using a machine andapparatus model and the actually measured value obtained from a powergeneration unit, wherein the ordinate represents electrical power outputand the abscissa represents time.

As shown in FIG. 8, at the early stage the estimated value and theactually measured value substantially coincide, however, depending onthe elapsed time, the deviation value between the estimated value andthe actually measured value increases, which implies that deteriorationof the gas turbine in the concerned power generation unit advances todecrease the performance thereof and no output according to one designcan be obtained anymore from the concerned power generation unit. In thepresent example, total performance of the gas turbine has beencalculated, however, performance of the individual machines such as thecompressor, combustor and turbine can be calculated for the evaluation.In such instance, a part whose performance is decreasing can bespecified, which is effective for identifying the causes of failure.

The efficiency diagnosis unit 19 converts the performance calculationresult determined by means of the machine and apparatus models intopower generation cost and compares the same with the power generationcost determined from the actual measurement value from the plant data.

FIG. 9 is a characteristic diagram showing an analysis example ofefficiency diagnosis performed in an efficiency diagnosis unit 19;wherein the ordinate represents power generation cost and the abscissarepresents output, and further wherein evaluation of the estimated valueby means of the machine and apparatus models and evaluation of theactually measured value obtained from the plant data are shown incomparison.

In FIG. 9, the power generation cost is defined as a fuel cost necessaryfor outputting a unit power generation amount and the fuel cost isdetermined in a predetermined time interval (for example, every onehour). Further, in the evaluation based on the actually measured valuein FIG. 9, the power generation cost is calculated by making use of theelectrical power output and fuel flow rate stored in the process valuedatabase 13 and the fuel cost obtained in advance, in that the powergeneration cost is calculated by multiplying the fuel cost by the fuelflow rate and dividing the multiplied result by the electric poweroutput. On the other hand, in the evaluation based on the estimatedvalue by means of the machine and apparatus models in FIG. 9, the powergeneration cost is determined by making use of the fuel flow rate of theactually measured value and the electrical power output of the estimatedvalue by means of the machine and apparatus models. When plotting therespective power generation costs determined according to both methodsfor every load, and if the performances of the machines and apparatusesare those as designed, the two plotted lines will coincide. The exampleas shown in FIG. 9 shows a case where the power generation costincreases due to performance deterioration of machines and apparatuses.

Subsequently, the preparation of the operation and maintenance plan bymaking use of the power generation cost calculated in the efficiencydiagnosis unit 19 is performed in the operation plan evaluation unit 25.Hereinbelow, the processing performed in the operation plan evaluationunit 25 will be explained.

The operation plan evaluation unit 25 uses the power generation costsdetermined on-line for the respective power generation units 41, 42, 51and 52, and prepares a plan from an economic point of view so as topositively operate a power generation unit or units having a lower powergeneration cost among the power generation units 41, 42, 51 and 52. Forexample, in the power generation unit 41 among the power generationunits 41, 42, 51 and 52, if deterioration of, for example, the gasturbine among its constituting machines and apparatus advances and theefficiency thereof decreases, a deviation is caused between the powergeneration cost based on the actually measured value determined from theprocess data in the power generation unit 41 and the power generationcost determined from the estimation value by means of the machine andapparatus models as explained above. In such instance, the operationplan evaluation unit 25 evaluates the economic loss due to theperformance deterioration according to the following equation (1);L 1 =C×A×D 1  (1)wherein,

L1: Economic loss due to performance deterioration (¥)

C: Power generation cost increase component due to the performancedeterioration (¥/MWd)

A: Power generation amount (actual resultant value) per day (MWd/day)

D1: Remaining days until subsequent periodic inspection (days).

In the equation (1), the power generation amount A per day is determinedby averaging the cumulative electric power output amount in respectiveoperation days. When multiplying the power generation amount A per daywith the remaining days D1 until the periodic inspection, an estimatedpossible power generation amount until the periodic inspection can becalculated. Information with regard to a plan on the periodic inspectionis stored in the periodic inspection information database 26.

FIG. 10 is a view for explaining storage contents of a periodicinspection database 26, and shows a structure of the periodic inspectioninformation data.

As shown in FIG. 10, the periodic inspection information data areinformation representing periodic inspection times already performed inthe past and periodic inspection times to be performed in the future,and based on the periodic inspection information data the remaining daysuntil the subsequent periodical inspection is calculated. The economicloss (L1) due to performance deterioration can be calculated bymultiplying the estimated power generation amount (A×D1) until thesubsequent periodic inspection by the power generation cost increasecomponent (C).

Subsequently, the operation plan evaluation unit 25 judges, in view ofthe total cost incurred for the operation and maintenance, whetheroperation of one power generation unit, for example, the powergeneration unit 41 has to be stopped and the machines and apparatusesand the parts thereof have to be exchanged or the operation thereof hasto be continued under the performance deteriorating condition. In thisinstance, the operation plan evaluation unit 25 calculates the cost inassociation with the change of the machines and apparatuses or the partsthereof with reference to the machine and apparatus information database27.

FIG. 11 is a view for explaining storage contents of a machine andapparatus database 27, and shows a structure of the machine andapparatus information data.

As shown in FIG. 11, the machine and apparatus information data areconstituted by manufacturer and type, purchased price and days necessaryfor installation work for every machine and apparatus and part thereof.In this instance, the cost in association with the exchange of themachines and apparatuses and the parts thereof is a sum of the currentprice of the machine and apparatus or the parts thereof in view ofdepreciation and the loss of electric power sales opportunity because ofthe power generation stoppage due to the exchange work, and is expressedby the following equation (2);L 2=P×(1−R)+A×D 2 ×E  (2)wherein,

L2: Economic loss (¥) in association with machine and apparatus/partexchange

P: Purchase price (¥) of exchanging machine and apparatus/parts

R: Consumed lifetime value (normalized value)(−)

A: Power generation amount per day (actual resultant value)(MWd/day)

D2: Days required for installation work (day)

E: Sales price of electric power (¥/MWd).

In the equation (2), with regard to the purchase price (P) of themachine and apparatus and parts, the information stored in the machineand apparatus information database 27 is referred to. The depreciationis evaluated in view of the remaining lifetime and uses the alreadyconsumed lifetime (R) as a parameter therefor. The consumed lifetimevalue (R) is a normalized value, and under a brand-new condition whenbeginning use, the value is 0 and the value increases depending on theuse years and becomes 1 when the exchange level has been reached.Namely, the consumed lifetime value (R) of 1 implies that the concernedmachine and apparatus have been used up and no value remains there. Acalculation method of the consumed lifetime value (R) will be explainedlater. Further, with regard to the loss of electric power salesopportunity, the power generation amount not generated because of theexchange of the machine and apparatus or the parts thereof can becalculated by multiplying the power generation amount (A) per day by thenumber of days (D2) required for installation work stored in the machineand apparatus information database 27, and when the electric power salesprice (E) is multiplied by the above calculated non-power generationamount, the economic loss in association with the exchange of themachine and apparatus or the parts thereof can be calculated.

The operation plan evaluation unit 25 compares the economic loss (L1)due to the performance deterioration with the economic loss inassociation with the exchange of the machine and apparatus or the partsthereof. When the performance deterioration of the power generation unitadvances and the economic loss (L1) exceeds the economic loss (L2), theoperation plan evaluation unit 25 plans to stop the operation of thepower generation unit and to exchange the machine and apparatus or theparts thereof, and further plans to compensate the power generationamount decreasing component due to the operation stoppage of the powergeneration unit with a power generation amount increasing by other powergeneration unit or units.

Further, the service center 1 uses the remaining lifetime of the machineand apparatus or the parts thereof as one of the parameters forpreparing the operation plan. Hereinbelow, the processing of calculatingthe remaining lifetime will be explained.

In the service center 1, the remaining lifetime diagnosis unit 20performs evaluation of the remaining lifetime of machines andapparatuses or the parts thereof, and evaluates the remaining lifetimeof the power generation unit based on the remaining lifetime evaluationdata for the respective power generation units stored in the materialinformation database 15.

FIG. 12 is a view for explaining storage contents of a materialinformation database 15, and shows the structure of the materialinformation data, namely the remaining lifetime evaluation data.

The parts such as the gas turbine, which are subjected to hightemperatures during the operation thereof, are caused of thermal fatiguedamage induced by thermal stress variation in association with theapplied temperature as well as caused of creep damage which advancesdepending on the height of the applied temperature and duration timethereof. These damages induce damages such as cracks if a predeterminedcritical value is exceeded and can cause a significant accident.

As shown in FIG. 12, the remaining lifetime evaluation data areconstituted by graphs representing accumulation of the thermal fatiguedamage and the creep damage in the respective power generation unit (gasturbine). In the graph of the thermal fatigue damage, the ordinaterepresents normalized thermal fatigue value, and the abscissa representsaccumulation value of exhaust gas temperature variation rate for every10 sec., and it is defined that when the thermal fatigue damage valuereaches 1, it is determined that the material endurance with respect tothe thermal fatigue damage has reached its critical value. Namely, theaccumulation value of the exhaust gas temperature variation rate in thegas turbine is a value obtained in such a manner that after the absolutevalue difference between the current exhaust gas temperature value andthat of before 10 sec. (representing variation rate in 10 sec.) ismultiplied by a normalized constant and the multiplication results areadded for every 10 sec., therefore, the thermal fatigue damage valuesimply increases depending on lapse of time.

Further, in the graph representing the creep damage, the ordinaterepresents normalized creep damage value, the abscissa representsaccumulated value of exhaust gas temperature for every 10 sec., and whenthe creep damage value reaches to 1, the material endurance with regardto the creep damage reaches to a critical value. The creep damage valuesimply increases depending on lapse of time. The consumed lifetime of agas turbine is determined by the sum of the thermal fatigue damage valueand the creep damage value by taking into account both influences by thethermal fatigue damage and by the creep damage. Namely, the consumedlifetime (R) is determined by the following equation (3);R=H+C  (3)wherein,

H: Thermal fatigue damage value (normalized value)

C: Creep damage value (normalized value).

FIG. 13 is a graph obtained by plotting variation condition of lifetimeconsumption value with respect to time as determined according to theabove processing, and shows an analysis example performed by theremaining lifetime diagnosis unit 19.

The consumed lifetime value of a brand-new gas turbine at the time ofinstallation is 0 and the value gradually increases through repetitionof such operations including temperature variation as startingup/stopping and load adjustment in addition to usual operation. In orderto evaluate the remaining lifetime of a gas turbine, based on theconsumed lifetime until now, a possible consumed lifetime thereafter isextrapolated and estimated according to the mathematical formularepresenting the consumed lifetime value, and the remaining lifetime isdetermined by the remaining time until the estimated result reaches tothe consumed lifetime value of 1 representing the exchange level.

In the service center 1, the operation plan evaluation unit 25 obtainsthe remaining lifetime data evaluated by the remaining lifetimediagnosis unit 20 and prepares the operation plan by making use of theobtained remaining lifetime.

FIG. 14 is a flow chart showing a processing flow when an operation planevaluation unit 25 prepares an operation plan for a certain powergeneration unit by making use of remaining lifetime data.

The flow chart will be explained with reference to FIG. 14, at first instep S1 the operation plan evaluation unit 25 obtains the remaininglifetime data evaluated by the remaining lifetime diagnosis unit 20 andcalculates the remaining lifetime days.

Subsequently, in step S2, the operation plan evaluation unit 25determines the days until the subsequent periodic inspection for theconcerned power generation unit with reference to the periodicinspection information database 26 and judges whether the calculatedremaining lifetime days are larger or shorter than the determined daysuntil the subsequent periodic inspection. Then, if it is judged that theremaining lifetime days are longer than the days until the subsequentperiodic inspection (Y), the process moves to the next step S3, on theother hand, if it is judged that the remaining lifetime days are shorterthan the days until the subsequent periodic inspection (N), the processmoves to the next step S4.

Subsequently, in step S3, the operation plan evaluation unit 25 preparesan operation plan for the concerned power generation unit to perform ausual operation and ends the series of processings in the flow chart.

Further, in step S4, the operation plan evaluation unit 25 reduces themaximum power generation amount in the concerned power generation unitby 25% and sets the same at 75% of the current power generation mount,and further reduces the load adjustment amount which varies depending onthe power demand by 25% and sets the same at 75% of the current loadadjustment amount, and prepares an operation plan which intends toprolong the remaining lifetime of the concerned power generation unit.

In the subsequent step S5, the operation plan evaluation unit 25 judgeswhether or not the maximum power generation amount in the concernedpower generation unit has been reduced by 100%. Then, if it is judgedthat the maximum power generation amount has been reduced by 100% (Y),the process moves to the subsequent step S6, on the other hand, if it isjudged that the maximum power generation amount has not yet been reducedby 100% (N), the process moves to another step S7.

In step S6, the operation plan evaluation unit 25 repeats the process instep S4 four times which will be explained later, even through repeatingthe processings if the end of the lifetime is reached, the operationplan evaluation unit 25 prepares an operation plan to stop the operationof the concerned power generation unit and ends the series ofprocessings in the flow chart.

Further, in step S7, the operation plan evaluation unit 25 prepares anoperation plan which permits the continued operation of the concernedpower generation unit for a week. Then, after a week when completing theoperation plan, the process returns to step S1 and the operation planevaluation unit 25 again causes to repeat steps following step S1.

In parallel with the above operation plan, the operation plan evaluationunit 25 prepares an operation plan in which another power generationunit having a higher power generation efficiency is positively selectedfor operation based on the power generation efficiency of the respectivepower generation units calculated in on-line. For example, as shown inFIG. 9, if the power generation amount (output) of a power generationunit is reduced, a reduction of the power generation efficiency iscaused (in other words cost increase) regardless of the performancedeterioration due to abnormality. For this reason, a probability ofcontinuing operation of the power generation unit is reduced of whichpower generation amount is adjusted to be reduced based on the remaininglifetime. Then, the operation plan evaluation unit 25 prepares amaintenance plan for performing an exchange of the machine and apparatusor the parts thereof for the power generation unit of which operation isjudged to be stopped according to the remaining lifetime diagnosisresult for the respective power generation units.

The above explanation shows an example in which, when preparing anoperation and maintenance plan for power generation units by making useof the remaining lifetime data, deterioration of the machine andapparatus or the parts thereof advances more than that estimated and theexchange timing is hastened. When preparing a usual operation andmaintenance plan for power generation units, it is planned based on theremaining lifetime data to exchange the machine and apparatus or theparts thereof at the time of the periodic inspection, however, if theend of the remaining lifetime comes earlier than that estimated becauseof changes in operational circumstances it is possible to prepare anoperation plan which prevents the machine and apparatus or the partsthereof from exceeding their lifetime. Therefore, the operation andmaintenance plan aiding system for a power generation installationaccording to the present embodiment can avoid unpredictablecircumstances, which causes unplanned outages of the power generationunit due to an abnormality caused by the use of the machine andapparatus or the parts thereof exceeding their lifetimes, and can alsoavoid the economic loss caused by the unplanned outage of the powergeneration unit.

Contrary to the above example, an example can be prepared in which,based on remaining lifetime diagnosis result evaluated in real time, theexchange timing of the machine and apparatus or the parts thereof can beprolonged. For example, since a gas turbine is subjected to a hightemperature and the deterioration thereof advances rapidly, an exchangestandard time (for example, an accumulated operation time of 50,000hours) is set in advance, and exchange of the machine and apparatus orthe parts thereof is performed during the periodic inspection so as notto exceed the standard time. In such instance, if the remaining lifetimeof the machine and apparatus or the parts thereof remains long, it isnot necessarily required to exchange the machine and apparatus or theparts thereof when the standard time is reached, and the exchange timingcan be extended. In such instance, in comparison with the exchange ofthe machine and apparatus or the parts thereof with reference to thestandard time, the maintenance cost can be reduced.

Further, the service center 1 uses failure frequency of the machine andapparatus as one of the parameters for preparing an operation plan.Hereinbelow, the processing for calculating the failure frequency of themachine and apparatus will be explained.

In the service center 1, the failure frequency evaluation unit 21evaluates the failure frequency of the machine and apparatus.

FIG. 15 is a view for explaining storage contents of a failureinformation database 16, and shows a structure of the failureinformation data.

As shown in FIG. 15, the failure information data show failure historiescaused in the respective power generation units, for example, at thefirst power generation unit in power generation plant A on Sep. 10, 2000a packing deterioration in an A company manufactured valve of type VL0010 was caused and the same was repaired and further it is indicatedthat the same valve was exchanged on Mar. 20, 1992. According to thecontents of the failure information data it is understood that the valvehas failed after about eight years and six months of use. Similarinformation is indicated with regard to the pump in the second powergeneration unit in the power generation plant B.

The failure frequency evaluation unit 21 evaluates with how muchprobability (once in how many years) a failure of the respectivemachines and apparatuses or the parts thereof is caused by making use ofthe data stored in the failure information database 16 and supplies theevaluation result to the operation plan evaluation unit 25.

The operation plan evaluation unit 25 evaluates whether the machine andapparatus or the parts thereof in the respective power generation unitscan be used without failure up to which periodic inspection timing inthe future by making use of the evaluation result supplied from thefailure frequency evaluation unit 21 and the reference result of theperiodic information database 26. Thereafter, when it is estimatedaccording to the failure probability of the machines and apparatuses orthe parts thereof that there are machine and apparatus or the partsthereof which only endures up to the timing of the subsequent periodicinspection, exchange of the machine and apparatus or the parts thereofis planned.

Further, the service center 1 uses a priority of manufacturers as one ofthe parameters for preparing the operation plan. Hereinbelow, theprocessing for calculating the priority of manufacturers will beexplained.

In the service center 1, the manufacturer priority evaluation unit 22evaluates priority of manufacturers based on the respective manufacturerinformation stored in the manufacturer information database 17.

FIG. 16 is a view for explaining storage contents of a manufacturerinformation database 17, and shows a structure of the manufacturerinformation data.

As shown in FIG. 16, in the manufacturer information data, with respectto the respective machines and apparatuses or parts thereof, thereliability and maintenance capacity for every manufacturer areevaluated by making use of A, B and C as evaluation references. In thisinstance, point 10 is assigned for A, point 5 for B and point 0 for C,and by determining the total points the priority of the manufacturersare determined according to the total points.

When the operation plan evaluation unit 25 selects a power generationunit for operation and if the manufacturer priority of the machine andapparatus or the parts thereof used in the power generation unit ishigh, the operation plan evaluation unit 25 prepares a plan whichpositively selects the concerned power generation unit for theoperation.

As has been explained hitherto, the operation and maintenance planaiding system for a power generation installation according to thepresent embodiment uses the performance diagnosis result, the remaininglifetime diagnosis result, the failure frequency and the priority ofmanufacturers when preparing an operation and maintenance plan for therespective power generation units.

FIG. 17 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a second embodiment of thepresent invention.

In the embodiment as shown in FIG. 17, the power generation unit 41includes two shafts 61 and 62, the power generation unit 42 includes twoshafts 71 and 72, the power generation unit 51 includes shafts 81 and 82and the power generation unit 52 includes shafts 91 and 92, and whereinthe power generation amount in the respective power generation units 41,42, 51 and 52 is adjusted for every shafts 61, 62, 71, 72, 81, 82, 91and 92. Further, in FIG. 17 the same or equivalent elements as those inFIG. 1 are denoted by the same reference numerals.

In FIG. 17, the shafts 61, 62, 71, 72, 81, 82, 91 and 92 designaterotating shafts for transferring motive power of turbines to generators,and each of the power generation units 41, 42, 51 and 52 includes aplurality of generators and each of the plurality of generators iscoupled with one or a plurality of turbines. For such power generationunits 41, 42, 51 and 52, when the power generation amount is set forevery shafts 61, 62, 71, 72, 81, 82, 91 and 92, namely for everygenerator, an extremely fine operation and maintenance plan can beprepared. For example, a plan can be prepared such that one of theplurality of shafts 61, 62, 71, 72, 81, 82, 91 and 92 constituting thepower generation units 41, 42, 51 and 52 is stopped for operation andthe operation of the other shafts is continued

In this instance, since the rest of the operation of the system foraiding in the preparation of operation and maintenance plan for a powergeneration installation of the second embodiment as shown in FIG. 17 issubstantially the same as that of the operation and maintenance planpreparation aiding system for a power generation installation of thefirst embodiment as has already been explained above, the explanation ofthe operation of the second embodiment is omitted.

FIG. 18 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a third embodiment of thepresent invention.

In the embodiment shown in FIG. 18, one power supply command center isprovided for each of the power generation plants 4 and 5, in that apower supply command center 3 is provided for the power generation plant4 and a power supply command center 7 is provided for the powergeneration plant 5. Further, in FIG. 18 the same or equivalent elementsas those in FIG. 1 are denoted by the same reference numerals.

In the third embodiment, the service center 1 separately determines thepower generation amount of the power generation units 41 and 42 whichare under control of the power supply command center 3 and the powergeneration amount of the power generation units 51 and 52 which areunder control of the power supply command center 7 in response to thepower generation amount required by the respective power supply commandcenters 3 and 7 and being transmitted via the communication network 6,and transfers the determined result to the respective power supplycommand centers 3 and 7 via the communication network 6.

In this instance, since the rest of the operation of the system for apower generation installation of the third embodiment as shown in FIG.18 is substantially the same as that of the system for a powergeneration installation of the first embodiment as has already beenexplained above, the explanation of the third embodiment is omitted.

FIG. 19 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a fourth embodiment of thepresent invention.

In the embodiment as shown in FIG. 19, no power supply command center isprovided, instead thereof operation planning sections 43 and 53 areprovided for the respective power generation plants 4 and 5. A powersupply command center has a role to adjust power generation amount ofpower generation units under its control in response to power demandwhich varies moment by moment. In constant, in the present embodiment,the operation planning sections 43 and 53 function to operate therespective power generation units 41, 42, 51 and 52 according to a powergeneration plan determined in advance.

In this instance, since the rest of the operation of the operation andmaintenance plan preparation aiding system for a power generationinstallation of the fourth embodiment as shown in FIG. 19 issubstantially the same as that of the system for a power generationinstallation of the first embodiment as has already been explainedabove, the explanation of the operation of the fourth embodiment isomitted.

FIG. 20 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance for a powergeneration installation representing a fifth embodiment of the presentinvention.

As shown in FIG. 20, the present operation and maintenance planningpreparation aiding system for a power generation installation isconstituted by a common service center 1 which performs the business ofpreparing an operation and maintenance plan, A electric power generationcompany 104 including two power generation units 41 and 42 and one powersupply command center (central supply) 43, B electric power generationcompany 105 including two power generation units 51 and 52 and one powersupply command center (central supply) 53 and a communication network 6such as an internet. In the present embodiment, the service center 1,the power generation units 41 and 42, the power generation units 51 and52 and the power supply command centers 43 and 54 are selectivelyconnected to the communication network 6.

The A electric power generation company 104 requests the service center1 the business of preparing an operation and maintenance plan for theowning power generation units 41 and 42 as well as the B electric powergeneration company 105 requests the service center 1 the business ofpreparing an operation and maintenance plan for the owning powergeneration units 51 and 52.

Respective exemplary constitutions of the power generation unit 41 andthe common service center 1 as shown in FIG. 20 are the same as thoseshown in FIGS. 2 and 3.

FIG. 21 is a view for explaining storage contents of another processvalue database as shown in FIG. 3 and shows a structure of the processdata.

As shown in FIG. 21, each of the process data is assigned a processnumber representing ID for discriminating process values for every powergeneration company and for every power generation unit and is managedaccording to the process number. In the present embodiment, the servicecenter 1 obtains process data in a predetermined cycle from therespective power generation units 41, 42, 51 and 52 and in the presentembodiment, as will be seen from the contents with regard to the time ofthe process data stored in the process value database 13, the servicecenter 1 obtains the process data in a cycle of 1 sec.

The power supply command center 43 of A electric power generationcompany 104 and the power supply command center 53 of B electric powergeneration company 105 transmit a power amount required to be suppliedby the owning power generation units 41, 42, 51 and 52 as respectivepower demand information to the service center 1 via the communicationnetwork 6. Since this power demand information varies over timedepending on power demand, the information is transmitted in apredetermined cycle, for example, every 1 sec. to the service center 1.The service center 1 receives the power demand information via the firewall 11 at the power demand amount receiving unit 23, and supplies thereceived power demand information to the operation plan evaluation unit25. In this instance, the operation plan evaluation unit 25 distributesfor each electric power generation company 104 and 105 power generationamounts for the respective power generation units 41, 42, 51 and 52 sothat the summed value of the power generation amounts of the respectivepower generation unit 41, 42, 51 and 52 coincides with the requiredvalue, and supplies the distribution result to the operation planinformation transmitting unit 24. The operation plan informationtransmitting unit 24 transmits the operation plan information, namelythe power generation amount information distributed to the owningrespective power generation units 41, 42, 51 and 52 for respectiveelectric power generation companies 104 and 105, to the power supplycommand centers 43 and 53 via the communication network 6. The powersupply command centers 43 and 53 confirm the contents of the operationplan information sent from the service center 1 and outputs the commandvalues of the power generation amount for the owning respective powergeneration units 41, 42, 61 and 52 according to the operation planinformation.

The explanation until now relates to the operation planning for theowning power generation units 41, 42, 51 and 52 for each electric powergeneration company 104 and 105 in response to power demand which variesover time in the operation and maintenance planning preparation aidingsystem for a power generation installation, however, other thanoperating the owning power generation units, it is sometimes true thatthe total cost for the operation and maintenance can be reduced if theelectric power is supplied from the power generation units owned by theother, in such instance the operation plan information transmission unit24 in the service center 1 transmits the determined operation plan tothe respective power supply command centers 43 and 53 for the respectiveelectric power generation companies 104 and 105, and, after receivingagreement from the respective electric power generation companies 104and 105, finalizes the operation plan. Thereafter, the power supplycommand centers 43 and 53 of the respective electric power generatorcompanies 104 and 105 output power generation amount command valuesaccording to the operation plan to the respective owning powergeneration units.

Hereinbelow, the role of the service center 1 performed for a pluralityof electric power generation companies will be explained.

FIG. 22 is a view for explaining storage contents of another designinformation database 18 as shown in FIG. 3 and shows a structure of thedesign information data.

As shown in FIG. 22, the design information data are constituted forevery electric power generation company by machines and apparatus andparts thereof constituting the respective power generation units andtheir supplying manufacturers and models for every machine, apparatusand part. For example, in the case of a first power generation unit(power generation unit 1) in A electric power generation company, aproduct of A company of type GT001 is employed as a gas turbine, and asparts constituting the gas turbine, a combustor of B company of typeCB003, a turbine of A company of type TB001 and a compressor of Acompany of type CP001 are employed.

FIG. 23 is a view for explaining storage contents of another periodicinspection database 26, and shows a structure of the periodic inspectioninformation data.

As shown in FIG. 23, the periodic inspection information data areinformation representing periodic inspection times already performed inthe past and periodic inspection times to be performed in the future,and based on the periodic inspection information data the remaining daysuntil the subsequent periodic inspection is calculated. The economicloss (L1) due to performance deterioration can be calculated bymultiplying the estimated power generation amount (A D1) until thesubsequent periodic inspection by the power generation cost increasecomponent (C).

Because of performance deterioration of a power generation unit when theoperation of the power generation unit is stopped, it is necessary toincrease the power generation amount of another power generation unitand to ensure that the power generation amount meets the electric powerdemand. In such instance, the following may happen in that the powergeneration cost (fuel cost per unit electric power output) increases, apower generation unit which is not used usually has to be operated andelectric power has to be purchased from another electric powergeneration company.

The operation plan evaluation unit 25 investigates a method of obtainingthe necessary power generation amount not only by taking into accountthe power generation cost of a company that owns the power generationunit that has been stopped, but also the power generation cost of apower generation unit owned by another electric power generationcompany. As has been explained above, the service center 1 calculatesthe power generation cost in real time based on the process valuesobtained from the power generation units. When stopping a powergeneration unit, at first with regard to respective power generationunits owned by itself and others, respective power generation unitshaving capacity to increase the power generation amount and having theminimum power generation cost are searched. Subsequently, with regard tothe power generation cost of the other company, a cost is calculated byadding a predetermined price on the power generation cost of its owncompany and the calculated cost is compared with the power generationcost of its own company. When the power generation cost of the othercompany is cheaper even in view of the added total price, it isdetermined that the electric power is to be purchased from the othercompany. Namely, the operation plan evaluation unit 25 prepares anoperation plan so as to increase the power generation amount of thepower generation unit of the other company. As has been explained above,with regard to the power generation amount adjustment between, forexample, A electric power generation company 104 and B electric powergeneration company 105, the service center 1 transmits the operationplan to the respective electric power generation companies 104 and 105via the communication network 6 and, after obtaining agreement from theelectric power generation companies 104 and 105, the operation plan isauthorized. With regard to the agreement of the electric powergeneration companies 104 and 105, the service center 1 confirms the samevia the communication network 6.

FIGS. 27( a) and 27(b) are characteristic diagrams showing a selectionprinciple of the power generation units. Now, when the maximum powergeneration amount and the load adjustment amount of a certain powergeneration unit are decreased and if an electric power shortage as shownin FIG. 27( a) is caused, the electric power shortage is supplemented asshown in FIG. 27( b), while dividing the supplementing electric powerinto base increase and peak response. With regard to the base increase,a power generation unit with a low power generation cost is selected toincrease the maximum power generation amount, and with regard to thepeak response, a power generation unit having a longer remaininglifetime is selected to increase the load follow-up property.

In parallel with the above operation plan, the operation plan evaluationunit 25 prepares an operation plan in which another power generationunit having a higher power generation efficiency is positively selectedfor operation based on the power generation efficiency of the respectivepower generation units calculated in on-line. For example, as shown inFIG. 9, if the performance of a power generation unit is deteriorated,the power generation efficiency thereof is also reduced, therefore, aprobability of operating such power generation unit is reduced. Then,the operation plan evaluation unit 25 prepares a maintenance plan forperforming exchange of the machine and apparatus or the parts thereoffor the power generation unit of which operation is judged to be stoppedaccording to the remaining lifetime diagnosis result for the respectivepower generation units.

Generally, a power generation unit used for supplementing the powergeneration amount and the load adjustment is selected among the powergeneration units owned by itself, however, when such supplement can notbe compensated by the power generation units commonly owned, anoperation plan in which electric power is procured from the powergeneration units owned by another is prepared. In such instance, theprice of the electric power is differentiated between a case wherein apredetermined amount of electric power is supplied for the base increaseand a case wherein the supplied electric power varies depending on timefor the peak response. Namely, with regard to the peak response, sincethe load is frequently varied which likely shortens the lifetime of themachine and apparatus or the parts thereof, therefore, the electricpower price is determined by adding a predetermined value on theordinary price.

The above explanation shows an example in which, when preparing anoperation and maintenance plan for power generation units by making useof the remaining lifetime data, deterioration of the machine andapparatus or the parts thereof advances more than that estimated and theexchange timing is hastened. When preparing a usual operation andmaintenance plan for power generation units, it is planned based on theremaining lifetime data to exchange the machine and apparatus or theparts thereof at the time of the periodic inspection, however, if theend of the remaining lifetime comes earlier than that estimated becauseof changes in operational circumstances, it is possible to prepare anoperation plan which prevents usage of the machine and apparatus or theparts thereof exceeding their lifetime. Therefore, the operation andmaintenance plan preparation aiding system for a power generationinstallation according to the present embodiment can avoid unpredictablecircumstances which causes unplanned outage of the power generation unitdue to an abnormality caused by the use of the machine and apparatus orthe parts thereof exceeding their lifetimes, and can also avoid theeconomic loss caused by the unplanned outage of the power generationunit.

Contrary to the above example, an example can be prepared in which,based on remaining lifetime diagnosis result evaluated in real time, theexchange timing of the machine and apparatus or the parts thereof can beprolonged. For example, since a gas turbine is subjected to a hightemperature and the deterioration thereof advances rapidly, an exchangestandard time (for example, an accumulated operation time of 50,000hours) is set in advance, and exchange of the machine and apparatus orthe parts thereof is performed during the periodic inspection so as notto exceed the standard time. In such an instance, if the remaininglifetime of the machine and apparatus or the parts thereof remains long,it is not necessarily required to exchange the machine and apparatus orthe parts thereof, when the standard time is reached and the exchangetiming can be extended. In such an instance, in comparison with theexchange of the machine and apparatus or the parts thereof withreference to the standard time, the maintenance cost can be reduced.

Further, the service center 1 uses failure frequency of the machine andapparatus as one of the parameters for preparing an operation plan.Hereinbelow, the processing for calculating the failure frequency of themachine and apparatus will be explained.

In the service center 1, the failure frequency evaluation unit 21evaluates the failure frequency of the machine and apparatus.

FIG. 24 is a view for explaining storage contents of another failureinformation database 16, and shows a structure of the failureinformation data.

As shown in FIG. 24, the failure information data show failure historiescaused in the respective power generation units, for example, at thefirst power generation unit in power generation company A on Sep. 10,2000 a packing deterioration in an A company manufactured valve of typeVL 0010 was caused and the same was repaired and further it is indicatedthat the same valve was exchanged on Mar. 20, 1992. According to thecontents of the failure information data, it is understood that thevalve has failed after about eight years and six months of use. Similarinformation is indicated with regard to the pump in the second powergeneration unit in the power generation company B.

The failure frequency evaluation unit 21 evaluates the probability (oncein how many years) of a failure of the respective machines andapparatuses or the parts thereof by making use of the data stored in thefailure information database 16 and supplies the evaluation result tothe operation plan evaluation unit 25.

As has been explained hitherto, although the operation and maintenanceplan preparation aiding system for a power generation installationaccording to the present embodiment uses the performance diagnosisresult, the remaining lifetime diagnosis result, the failure frequencyand the priority of manufacturers when preparing an operation andmaintenance plan for the respective power generation units for everyelectric power generation companies 104 and 105, it is cost advantageousif adjusting the power generation units owned by another company andprocuring the electric power from the other, and an operation andmaintenance plan over the plurality of electric power generationcompanies 104 and 105 is prepared.

When the electric power is procured from the other company, payment ofthe electric power fee between the electric power generation companies104 and 105 is necessitated, however, the electric power procurementusually occurs mutually between the plurality of electric powergeneration companies 104 and 105, it will be unnecessary to pay theelectric power fee at every procurement, and it will be sufficient if,after offsetting debits and credits for a predetermined period, forexample, every one year, the balance is paid as the electric power fee.

In this instance, the service center 1 settles the agreement betweenthese electric power generating companies 104 and 105 and prepares aplan so that the total costs for operation and maintenance of therespective electric power generation companies 104 and 105 areminimized.

FIG. 25 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a sixth embodiment of thepresent invention.

In the embodiment as shown in FIG. 25, the power generation unit 41includes two shafts 61 and 62, the power generation unit 42 includes twoshafts 71 and 72, the power generation unit 51 includes shafts 81 and 82and the power generation unit 52 includes shafts 91 and 92, wherein thepower generation amount in the respective power generation units 41, 42,51 and 52 is adjusted for every shaft 61, 62, 71, 72, 81, 82, 91 and 92.Further, in FIG. 25 the same or equivalent elements as those in FIG. 20are denoted by the same reference numerals.

In FIG. 25, the shafts 61, 62, 71, 72, 81, 82, 91 and 92 designaterotating shafts for transferring motive power of turbines to generators.Each of the power generation units 41, 42, 51 and 52 includes aplurality of generators and each of the plurality of generators iscoupled with one or a plurality of turbines. For such power generationunits 41, 42, 51 and 52, when the power generation amount is set forevery shaft 61, 62, 71, 72, 81, 82, 91 and 92, namely for everygenerator, an extremely fine operation and maintenance plan can beprepared. For example, a plan can be prepared such that one of theplurality of shafts 61, 62, 71, 72, 81, 82, 91 and 92 constituting thepower generation units 41, 42, 51 and 52 is stopped for operation andthe operation of the other shafts is continued.

In this instance, since the rest of the operation of the operation andmaintenance plan preparation aiding system for a power generationinstallation of the sixth embodiment as shown in FIG. 25 issubstantially the same as that of the system for a power generationinstallation of the fifth embodiment as has already been explainedabove, the explanation of the operation of the sixth embodiment isomitted.

FIG. 26 is a block diagram showing a major constitution of a system foraiding in the preparation of an operation and maintenance plan for apower generation installation representing a seventh embodiment of thepresent invention.

In the embodiment as shown in FIG. 26 no power supply command center isprovided, instead thereof operation planning sections 43 and 53 areprovided for the respective power generation companies 104 and 105. Apower supply command center has a role to adjust the power generationamount of the power generation units under its control in response topower demand which varies moment by moment. In constant, in the presentembodiment, the operation planning sections 43 and 53 function tooperate the respective power generation units 41, 42, 51 and 52according to a power generation plan determined in advance.

In this instance, since the rest of the operation of the operation andmaintenance plan preparation aiding system for a power generationinstallation of the seventh embodiment as shown in FIG. 26 issubstantially the same as that of the system for a power generationinstallation of the fifth embodiment as has already been explainedabove, the explanation of the operation of the seventh embodiment isomitted.

According to the first aspect of the present invention the followingadvantage is obtained, in that, since the operation and maintenanceplans for the respective power generation units are prepared in theservice center based on the power generation efficiency evaluated andcalculated in real time, a secular change and a performance degradationdue to failure occurrences for the respective power generation units canbe taken into account, thereby, the operation cost thereof can bereduced in comparison with the conventional power generation system inwhich the operation and maintenance plans for the respective powergeneration units are prepared by making use of the plant data.

According to the second aspect of the present invention the followingadvantage is obtained, in that, when preparing the operation andmaintenance plans for the respective power generation units in theservice center based on the power generation efficiency evaluated andcalculated in real time, since the cost of economical loss due to theperformance degradation is calculated from the deviation value betweenthe process value estimated using the machine and apparatus model andthe measured value, the cost of economical loss is compared with thecost relating to the exchange of the machine and apparatus and the partsthereof and the operation and maintenance plan of the respective powergeneration units are prepared by making use of the comparison result,the total cost for the operation and maintenance can be reduced.

According to the third aspect of the present invention the followingadvantage is obtained, in that, when preparing the operation andmaintenance plans for the respective power generation units in theservice center based on the power generation efficiency evaluated andcalculated in real time, since the operation and maintenance plans areprepared based on the calculated remaining lifetime, an exchange timingof the machine and apparatus and the parts thereof can be determinedwith a high accuracy in comparison with the conventional powergeneration system in which exchange of the machine and apparatus and theparts thereof is performed with reference to an accumulated operationtime thereof, as a result, an abnormality occurrence due to the use ofthe machine and apparatus and the parts thereof exceeding their lifetimeand generation of economical loss due to unplanned outages caused by anabnormality of the machine and apparatus and the parts thereof can beprevented, moreover, an exchange in every predetermined period of themachine and apparatus, even though there is a remaining lifetime, isunnecessitated, thereby, the maintenance cost can be reduced.

According to the fourth aspect of the present invention the followingadvantage is obtained, in that, when preparing the operation andmaintenance plans for the respective power generation units in theservice center based on the power generation efficiency evaluated andcalculated in real time, since the operation condition for the machineand apparatus in its own power generation unit is modified based on theremaining lifetime of the machine and apparatus and the parts thereofnot only in its own power generation unit but also in another powergeneration unit, the operation and maintenance plans can be prepared sothat the total cost necessary for the operation and maintenance for therespective power generation units is minimized, the cost merit obtainedby the electric power generation by the electric power generationcompany can be increased in comparison with the conventional powergeneration system.

1. A system for aiding the preparation of operation and maintenanceplans for a power generation installation, comprising: means forobtaining plant data from a plurality of power generation units; meansfor determining deviation values between process values estimatedaccording to a machine and apparatus model by making use of the obtainedplant data and measured data for the every plurality of power generationunits; and means for comparing between a cost of economical loss causedby a power generation efficiency reduction of the concerned powergeneration unit calculated from the determined deviation value and acost relating to exchange of the machine and apparatus and the partsthereof in the concerned power generation unit.
 2. A system for aidingthe preparation of operation and maintenance plans for a powergeneration installation, comprising: means for obtaining plant data froma plurality of power generation units; means for estimating processvalues according to a machine and apparatus model by making use of theobtained plant data for the every plurality of power generation units;means for determining deviation values between the estimated values andmeasured values; means for calculating a cost of economical loss causedby a power generation efficiency reduction of the concerned powergeneration unit from the determined deviation value; means for comparingbetween the calculated cost of economical loss and a cost relating toexchange of the machine and apparatus and the parts thereof in theconcerned power generation unit; and means for preparing operation andmaintenance plans for the respective power generation units according tothe comparison result.
 3. A system for aiding the preparation ofoperation and maintenance plans for a power generation installationaccording to claim 1, wherein failure histories of the machine andapparatus or the parts thereof in the plurality of power generationunits are stored in a database, a failure probability of the machine andapparatus or the parts thereof is calculated by making use of thefailure histories stored in the database, and an operation andmaintenance plan for each of the power generation units is prepared inview of the calculated failure probability.
 4. A system for aiding thepreparation of operation and maintenance plans for a power generationinstallation according to claim 2, wherein failure histories of themachine and apparatus or the parts thereof in the plurality of powergeneration units are stored in a database, a failure probability of themachine and apparatus or the parts thereof is calculated by making useof the failure histories stored in the database, and an operation andmaintenance plan for each of the power generation units is prepared inview of the calculated failure probability.
 5. A system for aiding thepreparation of operation and maintenance plans for a power generationinstallation according to claim 1, wherein manufacturers of the machineand apparatus or the parts thereof in the plurality of power generationunits and superiority with regard to reliability and maintenancecapacity of the manufacturers are stored in a database and an operationand maintenance plan for each of the power generation units is preparedin view of the superiority of the manufacturers stored in the databasewhen evaluating the machine and apparatus or the parts thereof.
 6. Asystem for aiding the preparation of operation and maintenance plans fora power generation installation according to claim 2, whereinmanufacturers of the machine and apparatus or the parts thereof in theplurality of power generation units and superiority with regard toreliability and maintenance capacity of the manufacturers are stored ina database and an operation and maintenance plan for each of the powergeneration units is prepared in view of the superiority of themanufacturers stored in the database when evaluating the machine andapparatus or the parts thereof.
 7. A method of aiding the preparation ofoperation and maintenance plans for a power generation installation, themethod comprising the acts of: obtaining plant data from a plurality ofpower generation units; estimating process values according to a machineand apparatus model by making use of the obtained plant data for theevery plurality of power generation units; determining deviation valuesbetween the estimated values and measured values; calculating a cost ofeconomical loss caused by a power generation efficiency reduction of theconcerned power generation unit from the determined deviation value;comparing between the calculated cost of economical loss and a costrelating to exchange of the machine and apparatus and the parts thereofin the concerned power generation unit; and preparing operation andmaintenance plans for the respective power generation units according tothe comparison result.